The proposed research will enable the principal investigator to participate with scientists in Kenya on a research program aimed at the discovery of neuroendocrine mechanisms that serve to coordinate the tsetse pregnancy cycle. The peculiar reproductive strategy of tsetse requires a regulatory mechanism to coordinate egg maturation, larval development, milk synthesis, ovulation and parturition. The mother-larval interaction will be examined at the time of parturition to determine who (mother or larv) initiates the signal for parturition. Neurosecretory material from the female's brain will be tested as a possible source of a neurohormone that induces both ovulation and parturition. Since preliminary evidence suggests an important role for cyclic AMP as mediator of ovulation and parturition, cyclic nucleotides and agents that elevate cyclic nucleotide levels will be tested rigorously as regulatory messengers and endogenous levels of cylic AMP and cyclic GMP will be measured throughout the cycle. The role of insect hormones as abortifacients and regulators of the milk gland will be further tested by measuring endogenous levels of juvenile hormone and ecdysone throughout a pregnancy cycle and by exposing pregnant tsetse to exogenous supplies of growth regulators in an attempt to disrupt pregnancy.